[Stimulating effect of recombinant cytokine LIF on the mouse blastocysts during implantation]

We studied the effect of recombinant cytokine LIF (Leukemia inhibitory factor) on the isolated mouse embryos at the stages of middle and late blastocyst. We showed that this agent is necessary at the formation stage of normal trophoblast after the leaving of blastocysts from z. pellucida in vitro. This cytokine (10 ng/ml) results in the intensification of adhesion and proliferative activity of trophoblast cells. It is important for intercellular interactions with endometrium and for invasion of embryos into the uterus. The recombinant LIF has not remarkable influence upon cells of intracellular mass.